Different types of apparatus for pleating textiles and other materials are known in the art and have been used for many years. The patent to Read, South African Patent No. 643,093, issued Sept. 15, 1950, describes a pleater utilizing two pairs of intermeshed rollers that pleat the material with floating needles riding in slots in the rollers that stitch the material. Material is fed into the throat of the first pair of rollers which pleat and stitch the material with the floating needles. Then the material is passed between a second set of rollers to be carried out of the apparatus. Further turning of the rollers draws more material into the apparatus, pleating the material and driving it through the apparatus and onto the shank portion of the needles. The pleats of the material are caused to lie flat against each other because of the bunching which occurs due to the frictional resistance of the needles.
The patent to Durand, U.S. Pat. No. 4,323,021, issued Apr. 6, 1982, discloses an improvement to the Read device and incorporates additional supporting rollers to support two of the rollers that bend under the forces generated during pleating.
Both references describe a pleating apparatus which uses an S-shaped needle mounted in floating relation in the spaced, parallel grooves of the rollers. Neither of the references is concerned with the specific structure of the needle relating to the length thereof and critical relationship of the positioning of the eye of the needle relative to the rollers of the pleating apparatus or the positioning of the eye end of the needle relative to any other aspect of the needle. In both of the references, the eye end of the needle extends a considerable length beyond the arc prescribed by rotation of a point on the outer periphery of the lower roller. Such extended length creates significant frictional resistance to material flow, which results in the bunching of the material on the eye end of the needle.
This bunching causes significant frictional resistance to material flow with most materials. When the accumulated pleats fill the needle shaft, the pleating operation must be stopped in order to manually strip material off the end of the needles onto the trailing threads, thus clearing the needles to receive more pleats. This is a highly bothersome, but currently absolutely necessary, procedure which results in repeated interruptions, i.e., a series of short stop-and-go operations. As pleated material accumulates on the needle, resistance to material motion builds to such large forces that the accumulated pleats are compressed from the needle eye toward and against the rotating teeth of the last roller gear. These compressed pleats wedge into and under the small bottom roller and create such a severe impasse for roller rotation and material flow as to totally halt the operation. If further or forced operation is attempted, such large forces are generated that needles are broken or bent, and in some cases, the small rollers or the support members are also bent.
Another disadvantage of the bunching of material onto the needle, requiring manual stripping to remove the material from the needle, is that the use of self-threading needle eyes is prohibited. The manual stripping action very frequently pulls the thread from the eye, ruining the process. The decreased resistance to pleating the material brought about by the self-stripping aspect of the invention permits the utilization of self-threading eyes on the needle.
Additionally, if it were desired to design a machine having a larger capacity, one would increase the number of needles and lengthen the rollers. However, increasing the number of needles of the prior art devices increases the resistance to material flow, subsequently increasing the loading on the rollers and thus limiting the number of needles and the ultimate width of the material that can be pleated.
Applicants' device eliminates the problems associated with the frictional resistance inherent in the extended needle shanks of the above-discussed references by providing a needle for use in such machines which will eliminate the adverse frictional resistance therein.
Applicants' device uses a needle of predetermined length having its eye end positioned proximate an arc prescribed by rotation of a point on the periphery of the lower of a pair of upper and lower intermeshed exit rollers of the pleater. The positioning of the eye end of the needle proximate this arc permits the last roller of the set of intermeshed rollers to propel the material off the end of the needle, permitting uninterrupted operation and reduced resistance to operation.